Before Hadi bin MubarakQahtani exploded himself into an anonymous fireball, he was young and interested only in "fooling around."

Like many Saudis, he was said to have experienced a religious

awakening after the Sept. 11, 2001, attacks on the United States and dedicated himself to Allah, inspired by "the holy attack that demolished the foolish infidel Americans and caused many young men to awaken from their deep sleep," according to a posting on a jihadist Web site.

On April 11, he died as a suicide bomber, part of a coordinated insurgent attack on a U.S. Marine base in the western Iraq city of Qaim. Just two days later, "the Martyrdom" of Hadi bin MubarakQahtani was announced on the Internet, the latest requiem for a young Saudi man who had clamored to follow "those 19 heroes" of Sept. 11 and had found in Iraq an accessible way to die.

Hundreds of similar accounts of suicide bombers are featured on the rapidly proliferating array of Web sites run by radical Islamists, online celebrations of death that offer a wealth of information about an otherwise shadowy foe at a time when U.S. military officials say that foreign fighters constitute a growing and particularly deadly percentage of the Iraqi insurgency.

The account of Qahtani's death, like many other individual entries on the Web sites, cannot be verified. But independent experts and former government terrorism analysts who monitor the sites believe they are genuine mouthpieces for the al Qaeda-affiliated radicals who have made Iraq "a melting pot for jihadists from around the world, a training group and an indoctrination center," as a recent State Department report put it. The sites hail death in Iraq as the inspiration for a new generation of terrorists in much the same way that Afghanistan attracted Muslims eager to fight against the Soviet Union in the 1980s.

Who are the suicide bombers of Iraq? By the radicals' account, they are an internationalist brigade of Arabs, with the largest share in the online lists from Saudi Arabia and a significant minority from other countries on Iraq's borders, such as Syria and Kuwait. The roster of the dead on just one extremist Web site reviewed by The Washington Post runs to nearly 250 names, ranging from a 13-year-old Syrian boy said to have died fighting the Americans in Fallujah to the reigning kung fu champion of Jordan, who sneaked off to wage war by telling his family he was going to a tournament.

Among the dead are students of engineering and English, the son of a Moroccan restaurateur and a smattering of Europeanized Arabs. There are also long lists of names about whom nothing more is recorded than a country of origin and the word "martyr."

Some counterterrorism officials are skeptical about relying on information from publicly available Web sites, which they say may be used for disinformation. But other observers of the jihadist Web sites view the lists of the dead "for internal purposes" more than for propaganda, as British researcher Paul Eedle put it. "These are efforts on the part of jihadis to collate deaths. It's like footballers on the Net getting a buzz out of knowing somebody's transferred from Chelsea to Liverpool." Or, as Col. Thomas X. Hammes, an expert on insurgency with the NationalDefenseUniversity, said, "they are targeted marketing. They are not aimed at the West."

Many of the Arabs, according to the postings, were drawn to fight in Iraq under the banner of al Qaeda in Mesopotamia, the group run by Jordanian militant Abu MusabZarqawi that has taken credit for a gruesome series of beheadings, kidnappings and suicide attacks -- many of them filmed and then disseminated on the Internet in a convergence between the electronic jihad and the real-life war.

In recent days, the U.S. military in Iraq has stepped up its campaign against the Zarqawi network, launching an offensive in western Iraq in an area where foreigners are believed to be smuggled across the Syrian border and claiming to have arrested or killed nearly two dozen key Zarqawi lieutenants. At the same time, Iraq has been hit by a wave of suicide attacks causing about 400 deaths over the last two weeks, one of the deadliest periods since the U.S. invasion in 2003.

As the military has blamed much of the escalating violence on foreign fighters coming to Iraq, Zarqawi's group responded this week. "The infidels once again are claiming that foreign fighters are responsible for initiating the attacks and an increase [in foreign fighters] is the true danger," the Zarqawi media wing said in a May 10 Internet posting. But "the real danger," the posting said, is Zarqawi's overall following. And besides, it added, "who is the foreigner . . .? You are the ones who came to the land of the Muslims from your distant corrupt land."

U.S. military estimates cited by security analysts put the number of active jihadists at about 1,000, or less than 10 percent of the number of fighters in a mostly Iraqi-dominated insurgency. But military officials now say the foreigners are responsible for a higher percentage of the suicide bombings, and the online postings include few names of dead Iraqis affiliated with Zarqawi's group.

Many of the suicide bombers appear to have been novices in warfare, attracted by the relative ease of access to Iraq and the lure of quick martyrdom. "This is not al Qaeda's first team," said Hammes of the NationalDefenseUniversity. "These are the scrubs who could never get us in the States."

In a paper published in March, Reuven Paz, an Israeli expert on

terrorism, analyzed the lists of jihadi dead. He found 154 Arabs killed over the previous six months in Iraq, 61 percent of them from Saudi Arabia, with Syrians, Iraqis and Kuwaitis together accounting for another 25 percent. He also found that 70 percent of the suicide bombers named by the Web sites were Saudi. In three cases, Paz found two brothers who carried out suicide attacks. Many of the bombers were married, well educated and in their late twenties, according to postings.

"While incomplete," Paz wrote, the data suggest "the intensive

involvement of Saudi volunteers for jihad in Iraq." In a telephone interview, Paz said his list -- assembled from monitoring a dozen Islamic extremist Web forums -- now had more than 200 names. "Many are students or from wealthy families -- the same sociological characteristics as the Sept. 11 hijackers," he said.

The apparent predominance of Saudi fighters on the Internet lists has caused an alarmed reaction by Saudi officials, who fear a backlash from the Americans at the same time they are trying to convince the United States that they are working as allies against terrorism. While Saudi officials do not deny that Saudi citizens have taken up arms against the United States in Iraq, they argue that the long lists of Saudi dead could be a disinformation tactic or simply a recruiting tool used to lure Arab youth to Iraq by convincing them of how many others have already won a place in Paradise.

"Are there Saudis in Iraq? Yes, we know that. Absolutely. But are

there the numbers being bandied about? We really don't believe so," said a Saudi official who spoke on the condition of anonymity, citing the sensitivity of the subject.

"The Internet sites try to recruit people -- it's the best recruitment

tool," said Saudi security analyst NawafObaid. Obaid, who has worked closely with the government, said he found 47 cases of Saudis who were dead or injured reported in the kingdom's newspapers, far lower than Internet totals, and had concluded the overall number of Saudi jihadis in Iraq was in the hundreds. "But young guys, they read [on the Internet] we have thousands of Saudis there and think, 'I have to go, too.' "

Evan F. Kohlmann, a researcher who monitors Islamic extremist Web sites, has compiled a list of more than 235 names of Iraqi dead gleaned from the Internet since last summer, with more than 50 percent on his tally from Saudi Arabia as well. In some cases, he found photos or videos of dead foreign fighters posted online. One Kuwaiti policeman who died was featured in a Zarqawi propaganda video called "Winds of Change," while the bloodied corpse of a Turkish al Qaeda disciple, HabibAktas, was shown on another video celebrating his "martyrdom."

Some of the Web postings also include phone numbers so fellow Islamists can call a dead fighter's family and congratulate them. Kohlmann called several of the numbers. "I have lists and lists of foreign fighters, and it's no joke. Their sons went and blew themselves up in Iraq," he said.

Zarqawi's group has also regularly posted biographical sketches of its suicide bombers, such as that of Abu AnasTuhami, said to have died in a suicide attack on Iraq's Election Day in January. Tuhami, a Saudi orphan raised by his grandfather, was unusually saintly, as reported in the February online communique.

"O' brother, I love to sleep on the floor and I need no mattress," Tuhami was quoted as telling one fellow foreign fighter. He was to have been married in February. "Instead, he chose to be with the virgins of paradise," the announcement said. "He used to talk frequently about the virgins of paradise and their beauty, and he wished to drink a sip from the sustenance of paradise while a virgin beauty wiped his mouth."One Web forum examined by The Post, a site first registered to an Abu Dhabi individual on Sept. 18, 2001, and believed to attract postings from al Qaeda, presents a regularly updated list of the "Arab martyrs in Iraq." The forum, at http://www.qal3ah.net/ , was used by both Paz and Kohlmann in compiling their lists; other researchers also said they regularly consulted the site, which bills itself as a sort of town hall for the jihad-inclined.

Saudis were also the leading group on this list, representing 44 percent, followed by Syrians and Iraqis at less than 15 percent each. Many of the dead appeared to be young newcomers to jihad with stories like Qahtani's, though other listings detailed the deaths of veteran fighters who came through the al Qaeda training camps in Afghanistan before Sept. 11, including the father of AmmarSouri, the 13-year-old said to have died during last year's fighting in Fallujah.

Often the entries bragged about the number of Americans killed by the "lions from the martyrs' brigade," as in the case of Ahmed Said Ghamdi, a 20-year-old Saudi who was said to have given up his medical studies in Sudan to go to Iraq and was hailed as the "hero" of a Mosul suicide bombing of a mess tent that killed 22 people.

Another list, posted in February on the forum called Masada at http://www.alm2sda.net/ , listed a couple dozen senior Zarqawi lieutenants who had died -- most of whose names appear on the other Web lists. Among them was Abu Mohammed Lubnani, a Lebanese who had lived in Denmark before going to fight in Iraq and whose son was also killed, and Abu Ahmad Tabuki, who had been a key figure in the Afghan jihad against the Soviets.

Biographical details are often sketchy in the online obituaries, as is the case with Qahtani, the young Saudi said to have died April 11 while attacking a U.S. Marine base in the western Iraqi city of Qaim. The account of his death located by Kohlmann on the Internet does not say whether Qahtani was driving the commandeered dump truck that barreled onto the base, wreaking havoc before exploding, or whether he was in one of two other vehicles that blew up while another group of fighters opened fire on Marines.

It gives no more identifying details than his name -- indicating he was part of a well-known Saudi tribe that also produced the al Qaeda member known as the so-called 20th hijacker, Mohamed Qahtani, who was turned away from entering the country by suspicious U.S. airport officials in August 2001.

Five other Qahtanis have been reported killed in Iraq, including Muhammed bin AedhGhadifQahtani, a captain in the Saudi National Guard who allegedly used his guard identification badge to help gain entry into Iraq when he was stopped for questioning.